HUMAN BIOLOGY

Genes and disease: CanCer 437

seLf-Quiz Answers in Appendix VI

1. A tumor is.
   a. malignant by definition
   b. always enclosed by connective tissue
   c. a mass of tissue that may be benign or malignant
   d. always slow-growing


2. Cancer cells.
   a. lack normal controls over cell division
   b. secrete the growth factor angiogenin
   c. display altered surface proteins
   d. are not inhibited by contact with other cells
   e. all of the above


3. The onset of cancer seems to require the activity of an
   oncogene plus the absence or mutation of at least
   one.


4. Chemical carcinogens.
   a. include viral oncogenes
   b. can damage DNA and cause a mutation
   c. must be ingested in food
   d. are not found in foods


5. So far as we know, carcinogenesis is not triggered by
   .
   a. breakdowns in DNA repair d. protein deficiency
   b. a breakdown in immunity e. inherited gene
   c. radiation defects


6. Tumor suppressor genes.
   a. occur normally in cells
   b. promote metastasis
   c. are brought into cells by viruses
   d. only rarely affect the development of cancer


7. is the definitive method for detecting cancer.
   a. Blood testing c. Biopsy
   b. Physician examination d. Medical imaging


8. The most common therapeutic approaches to treating
   cancer include all of the following except.
   a. chemotherapy
   b. irradiation of tumors
   c. surgery to remove cancerous tissue
   d. administering doses of vitamins


9. The goal of immune therapy is to.
   a. cause defective T cells in the thymus to disintegrate
   b. activate cytotoxic T cells
   c. dramatically increase the numbers of circulating
   macrophages
   d. promote the secretion of monoclonal antibodies


10. Currently in the United States, cancer is the leading
    cancer diagnosed among adult females; cancer is the
    leading cancer most often diagnosed among adult males.
    a. lung; colon c. colon; lung
    b. breast; prostate d. breast; lung

CritiCaL tHinKinG

1. Look back at the discussion of aging and DNA repair in
   Chapter 17 and Chapter 21, then propose an explanation
   of the observation that higher rates of cancer are associated
   with increasing age.

reView Questions

1. How are cancer cells structurally different from normal
   cells of the same tissue? What is the relevance of altered
   surface proteins to uncontrolled growth?


2. What are the differences between a benign tumor and
   a cancerous one?


3. Write a short paragraph that summarizes the roles of proto-
   oncogenes, oncogenes, and tumor suppressor genes in
   carcinogenesis.


4. List the four main categories of cancer tumors.


5. What are the seven warning signs of cancer? (Remember
   the American Cancer Society’s clue word, CAUTION.)


6. Using the diagram below as a guide, indicate the major
   steps in cancer metastasis.

Step 3.

Step 2.

Step 1.

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